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借助ABAQUS有限元分析软件对几何形状复杂的5CrNiMo钢挤压模具淬火过程的温度场及热应力场进行数值模拟。计算综合考虑了非线性的材料热物性参数、力学性能参数、表面换热系数及相变潜热的影响。研究表明,淬火初期,工件表面与心部仅存在较小的温差,随淬火时间的延长,该温差不断增大,淬火约5 s时,该温差达到最大值,此时表面温度虽已降低到192℃,但心部温度仍高达780℃,此后该温差不断减小,淬火约460 s时,工件表面和心部温度趋于与介质相同的温度(20℃);淬火过程的热应力变化在工件内外表现为不同的特点,对于表面和心部节点,其主要表现为:表面先呈拉应力后呈压应力,心部先呈压应力后呈拉应力。
The temperature field and thermal stress field of 5CrNiMo steel extrusion die with complex geometrical shape were numerically simulated by ABAQUS finite element analysis software. The influence of non-linear material thermophysical parameters, mechanical performance parameters, surface heat transfer coefficient and latent heat of phase transformation is considered. The results show that there is only a small temperature difference between the workpiece surface and the heart at the initial stage of quenching. As the quenching time prolongs, the temperature difference increases continuously. When the quenching time is about 5 s, the temperature difference reaches the maximum, and the surface temperature is reduced to 192 ℃, but the heart temperature is still as high as 780 ℃, then the temperature difference decreases continuously. When the quenching time is about 460s, the surface and core temperature of the workpiece tend to be the same as that of the medium (20 ℃) The internal and external performance of the workpiece is characterized by different, for the surface and the heart of the node, its main performance: the surface was tensile stress was compressive stress, the heart was the first tensile stress after compressive stress.